Just tried the fantastic Elvis sandwich at Cafe Loftus at 15th & Sansom. It was so good! Toasted bread, chunky peanut butter (you can get creamy), banana slices and honey. I was in peanut butter heaven.
I haven't had their sandwiches since I usually just stop in for coffee, so I can't comment. There was a small article in Wednesday or Thursday's Metro paper with the headline "Adult PB&J" or something to that extent. They have it hanging by the register.
I know they stock several different kinds of nut butters and jams. Definitely worth researching :)